Diet Coke has more caffeine than Sprite: 46mg vs 0mg in the same 12 oz can. That is a 46mg gap, and since the cans match, the per-serving number is the whole story.
Diet Coke vs Sprite: the numbers
| Diet Coke | Sprite | |
|---|---|---|
| Caffeine per serving | 46mg per 12 oz can | 0mg per 12 oz can |
| Caffeine per fl oz | 3.8mg | 0.0mg |
| Servings to reach 400mg (FDA context) | 8.7 | n/a (caffeine-free) |
Sources: Diet Coke's figure is verified in our Diet Coke caffeine guide against Caffeine Informer (source); Sprite's figure is verified in our Sprite guide against Caffeine Informer (source).
The concentration gap is the striking part: Diet Coke packs roughly 383 times the caffeine per ounce. Sipping speed matters at that density; a 12 oz can finished in minutes hits differently than the same milligrams spread over a slow cup.
Which one should you pick?
Pick Sprite when you want the lighter dose or a slower ramp, and Diet Coke when you actually need the bigger hit and know your tolerance. If you are stacking either with other caffeinated drinks through the day, run the math against the 400mg reference rather than guessing.
For context, the FDA cites 400mg of caffeine a day as an amount generally not associated with negative effects in healthy adults. Tolerance and health vary, so treat these numbers as information, not advice.
Related reading
- Diet Coke: the full caffeine guide
- Sprite: the full caffeine guide
- The verified caffeine database
- Every drink compared: the comparisons index
FAQ
Does Diet Coke or Sprite have more caffeine? Diet Coke: 46mg per 12 oz can versus 0mg per 12 oz can for Sprite.
Which is stronger per ounce? Diet Coke, at about 3.8mg per fluid ounce versus 0.0mg for Sprite.
Comparing caffeine? The caffeine comparison tool puts hundreds of drinks side by side, and the caffeine curfew calculator can check your cutoff time for tonight.